# The World is Round

After an apple landed on his head, Isaac Newton came up with a theory about gravity, stating that it is a force which affects and changes the motion of something else.  Actually Sir Isaac Newton had his “eureka” moment concerning gravity, after he spent a lot of his time trying to figure out the slope of a curve that was constantly varying, however when he was formulating his Laws of Motion, there was no method available that would give him the exact slope at any one individual point on the curve and this is why he invented calculus.  Newton knew how to take an average, but he was not happy with finding the average speed of an apple falling from a tree, he wanted to know what the speed of an apple would be as it was constantly accelerating, at every point along the way and what would the apple’s velocity be when it was halfway to the ground.

When Newton wasn’t dodging falling apples, he thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from Earth, but that this power must extend much further than was usually thought.  Why not as high as the Moon he thought and if so, that must influence her motion and perhaps retain her in her orbit, whereupon he began calculating what would be the effect of that superposition.  Robert Hooke and Christopher Wren collaborated their experiments to explain planetary motion, because they disagreed with the inverse-square relation between gravitational force and distance which Newton proposed.  Since we live in a three-dimensional world, the Earth is not round, unless it is viewed from space.

Pythagoras was the first to propose that the Earth was round, because he believed the sphere was the most perfect shape, but he didn’t have any evidence to back up his radical claim.  Pythagoras made a contribution to music, concluding that small whole number ratios were the foundation for consonant sounds in strings as well as in volumes of air in pipes and water in vases.  Aristotle listed several arguments for a spherical Earth, those being that ships disappear hull first when they sail over the horizon, the Earth casts a round shadow on the moon during a lunar eclipse, and different constellations are visible at different latitudes and he also said that the Earth was the center of the universe.  Aristotle got some things wrong, as the Earth is not the center of the universe and planets don’t revolve around the Earth in circular patterns and heavier objects don’t fall faster than lighter objects, but Copernicus, Kepler and Galileo came around to correct him.

The size of Earth was determined by Eratosthenes of Cyrene which was based on the length of shadows at noon on the summer solstice and although this method was not the optimum way of measuring the circumference of the Earth, as the Sun was a lot closer than Eratosthenes thought it was, it was good enough for a ballpark answer.  The Earth’s tilt is perfectly positioned to give us different seasons which are pretty well balanced.  As Earth moves around the Sun, we get different seasons (Spring, Summer, Fall and Winter).

Aryabhata the elder a Hindu mathematician introduced the concept of sine in trigonometry using the word “jya” or “jiva” for a half-chord, which later became the term “jiva”.  Early Latin translations of Arabic mathematical treatises mistook this to be the Arabic word jaib, which meant bosom, fold or bay or it could be the opening of a woman’s garment at the neck.  Thus, jaib was translated into the Latin word sinus, which can mean “fold” draping of a loose, full garment or piece of cloth, “bosom” a woman’s chest, “bay” a body of water forming an indentation of the shoreline where the land curves inward, or even “curve”.

Einstein came along with his tenacious general theory of relativity and gravity suddenly became more complicated, because he made gravity a property of the universe, rather than being associated with individual bodies.  Mathematics is all about truth and beauty and building scientific and human connections and the Norwegian mathematician and researcher Marius Sophus Lie initiated lines of study involving integration of differential equations, transformation groups, and contact of spheres that have come to be called Lie theory, all of which has nothing to do with lying.

My conjecture is deep and profound, I speculated that the circumference of a circle is round.  My hypothesis seemed sound, the evidence was lost and never found, so the results of my efforts will never astound.  There is a dichotomy between yours and mine, but what belongs to you is yours and anything that belongs to me is mine.  Sometimes I wonder why I continue to do these multiple prompt posts, but then I remember that it could be just because the world is round and also that I am good at this.

Written for Sheryl’s Daily Word Prompt – Optimum, for Roger Shipp’s Daily Addictions prompt – Wren, for the Daily Spur prompt – Tenacious, for FOWC with Fandango – Because, for November Writing Prompts – Yours and mine, for Ragtag Community – Winter, for Di’s Three Things Challenge prompt words – Lying Well Chest and for Word of the Day Challenge Prompt – Radical.

## 8 thoughts on “The World is Round”

1. Yep Lying, Well and Chest three words that do not connotate directly to mathematics on the surface were all stuffed into this post. Well is easy and that could fit into any post, Lie theory has nothing to do with lying and I really had to dig deep to get chest in there. I stumbled on the shape of a woman’s bosom on her chest being compared to a curve like that of a sine wave and this made me happy. But then again a lovely bosom always seems to do the trick for me.

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1. Thanks Di, but it is not nearly as complicated as my third book “So You Want To Learn Calculus”.

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2. I for one am delighted you do because now that I’ve found you again, I want to keep visiting!

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